1. Field of the Invention
The present invention generally relates to a film-carrying system and a film-carrying device used therein; particularly, the present invention relates to a film-carrying system for a backlight module and a film-carrying device used therein.
2. Description of the Prior Art
Backlight modules are widely used in liquid crystal display (LCD) panels, buttons of cellular phones, advertising billboards, and any other devices that require a planar light source. In the recent years especially, the markets for flat panel displays are rapidly expanding. As a result, the need for LCD panels in the markets is largely increased at the same time. Furthermore, the functional and structural designs of the backlight modules used in the LCD panels have been diversified, in order to accommodate the emerging market demands for the LCD panels.
FIG. 1 shows a conventional design of a backlight module. As shown in FIG. 1, the backlight module usually includes a light source 70, a reflector plate 90, a frame 10, a light guide panel 20, and an optical film 50. The light source 70 is disposed above the reflector plate 90, for providing light to the backlight module. The light guide panel 20 and the optical film 50 are disposed above the light source 70, for directing the behaviors of the outputting light from the light source 70, such as the brightness, the direction, and the uniformity of the outputting light. In order to position the light source 70, the light guide panel 20, and the optical film 50 according to their relative positions, the light guide panel 20 and the optical film 50 is disposed on top of the frame 10, and the light source 70 is disposed with the frame 10 together.
As shown in FIG. 1, since the optical film 50 is usually thin in the thickness while the cross-sectional surface strength is not strong enough for providing sufficient surface tension, the optical film 50 is disposed right on top of the light guide panel 20, in order to stay flat inside the backlight module. However, some of the backlight modules used today are designed without the light guide panel 20 disposing inside. Therefore, it may be necessary for this type of backlight module to have a flat, light-transmittable, and board-like structure disposed inside for supporting the optical film. However, this kind of design will usually increase the manufacturing cost. Furthermore, even though the board-like structure is light-transmittable, it can not always provide a 100% transmittance rate, and which will ultimately affect the overall luminance intensity of the backlight module. Also, adding the board-like structure will increase the weight of the backlight module, which will eventually add more weight to the product using the backlight module.